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Biomimetic approach to inhibition of photooxidation in organic solar cells using beta-carotene as an additive
摘要： Recent efficiency records of organic photovoltaics (OPV) highlight stability as a limiting weakness. Incorporation of stabilizers is a desirable approach for inhibiting degradation - it is inexpensive and readily up-scalable. However, to date, such additives have had limited success. We show that β-carotene (BC), an inexpensive and green, naturally-occurring antioxidant, dramatically improves OPV stability. When compared to non-stabilized reference devices, the accumulated power generation in presence of BC of PTB7:[70]PCBM devices increases by an impressive factor of 6, due to stabilization of both the burn-in and the lifetime, and by a factor of 21 for P3HT:[60]PCBM devices, owing to a longer lifetime. Using electron spin resonance and time-resolved near-IR emission spectroscopies, we probed radical and singlet oxygen concentrations. We demonstrate that singlet oxygen sensitized by [70]PCBM causes the “burn-in” of PTB7:[70]PCBM devices, and that BC effectively mitigates it. Our results provide an effective solution to the problem that currently limits widespread use of OPV.
关键词： singlet oxygen,Organic solar cells,burn-in,antioxidant,stability
更新于2025-09-19 17:13:59
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Importance of Device Structure and Interlayer Design in Storage Stability of Naphthalene Diimide-based All-Polymer Solar Cells
摘要： While excellent thermal and mechanical stabilities of all-polymer solar cells (all-PSC) have been demonstrated, the storage stability of all-PSCs has rarely been studied. In this paper, the storage stability of all-PSCs is systematically investigated and compared to fullerene-based polymer solar cells (PCBM-PSCs). We identify that the efficient inverted type all-PSCs made with a molybdenum oxide (MoO3) anode interfacial layer can exhibit degradation over short periods of storage even under inert nitrogen-filled and dark conditions, while the control inverted PCBM-PSCs containing the same polymer donor (PDs) are relatively more stable. To elucidate the origin of the poor storage stability, morphological and electrical properties of all-PSCs are investigated. We reveal that the work function of MoO3 is largely changed during the storage because of the interaction between MoO3 and the underneath naphthalene dimide (NDI)-based PAs. This causes unfavorable energy-level alignment in devices, resulting in increased charge recombination and deteriorated charge collecting efficiency. To resolve this issue, we propose two effective strategies: i) introducing a passivation layer to physically separate the NDI-based PAs and MoO3, and ii) replacing MoO3 with an efficient polymer interlayer. We prove that the modified all-PSCs not only exhibit the excellent storage stability with high power conversion efficiency for more than 45 days, but also show high air-stability even without encapsulation. Our findings provide better understanding of the storage stability of all-PSCs and suggest future guidelines for efficient and burn-in free all-PSCs.
关键词： stability,burn-in degradation,all-polymer solar cells,storage lifetime,interlayers,naphthalene diimide polymers
更新于2025-09-16 10:30:52